Link Up and Listen!

When you finish this game, you can post your game results on Facebook. Challenge your friends!

Why are there three antennas in the game? And what are those spacecraft in the sky? Keep on reading to find out!

These are the Deep Space Network (DSN for short) of antennas that stay in touch with the many NASA spacecraft that are out exploring the solar system.

The spacecraft are so far away, that relative to Earth's rotation, they might as well be standing still. That's why the antennas that must stay in touch with them are located at three places around the Earth. As Earth turns, there is always one antenna in view of every spacecraft.

As Earth turns, each DSN location comes into "view" of some spacecraft. To talk and listen to a spacecraft, the DSN antenna must link up with the signal from the spacecraft's antenna. Then the DSN antenna must rotate to maintain that link as Earth continues to rotate through the day. Just when the DSN antenna is about to rotate out of view, the next DSN location on Earth's surface is rotating into view. The link is "handed over" to the "new" antenna before the "old" antenna loses it. That way, the spacecraft is always in touch with Earth.

When the DSN antenna is transmitting a message to the spacecraft, the link is called an "uplink." The uplink is for sending commands or new software programs to the spacecraft. When the spacecraft is sending its data and images down to the DSN antenna, the link is called a "downlink." An antenna "uplinks" instructions to the spacecraft and "downlinks" the spacecraft's data and images.

Play DSN Uplink-Downlink. Help the DSN to gather the data from these five missions: